1. Field of the Invention
The present invention relates to heat sink fastener adapted to secure a heat sink to a CPU holder and, more particularly, to such a heat sink fastener, which can easily be unfastened when unloading the heat sink.
2. Description of the Related Art
FIG. 1 illustrates the application of a heat sink fastener to secure a heat sink 3xe2x80x2 to a CPU holder 2xe2x80x2, keeping the heat sink 3xe2x80x2 in close contact with the CPU in the CPU holder 2xe2x80x2. According to this design, the heat sink fastener is comprised of an angled clamping plate 11xe2x80x2 and a vertical locking plate 12xe2x80x2. The angled clamping plate 11xe2x80x2 has one hooked end 111xe2x80x2 hooked in one of the two hook holes 21xe2x80x2 of the CPU holder 2xe2x80x2, and the other end pivoted to the vertical locking plate 12xe2x80x2. The vertical locking plate 12 has one end pivoted to the angled clamping plate 11xe2x80x2, and the other end terminating in a hooked portion 121 hooked in the other of the two hook holes 21xe2x80x2 of the CPU holder 2xe2x80x2. This structure of heat sink fastener is not satisfactory in function. When installed, the heat sink 3xe2x80x2 may not be tightly maintained in contact with the surface of the CPU in the CPU holder 2xe2x80x2. Further, when unloading the heat sink 3xe2x80x2, a special tool is needed to disengage the heat sink fastener from the CPU holder 2xe2x80x2.
The present invention has been accomplished to provide a heat sink fastener, which eliminates the aforesaid drawbacks. It is therefore one object of the present invention to provide heat sink fastener, which keeps the heat sink positively in close contact with the CPU when installed. It is another object of the present invention to provide a heat sink fastener, which can easily be unfastened. To achieve these and other objects of the present invention, the heat sink fastener comprises a narrow elongated stop plate adapted for engaging into one transversely extended groove of the heat sink, the stop plate having longitudinally and transversely extended end notches at two distal ends thereof and a rectangular locating hole on the middle, an elongated securement member, the securement member having two arched arms symmetrically provided at two distal ends thereof and adapted for engaging into two vertical grooves of the heat sink, the arched arms each having a top notch, which receives one longitudinal end notch of the stop plate, a bottom locating hole, and a distal end terminating in a hooked portion adapted for hooking in one hook hole of the CPU holder, a spring wire rod, the spring wire rod having two curved ends respectively hooked in the bottom locating holes of the arched arms of the elongated securement member, two torsional springs respectively mounted on the curved ends of the spring wire rod and stopped between the arched arms of the securement member and the spring wire rod, a pressure plate fastened to one longitudinal end notch of the stop plate and adapted for pressing by the user to force the securement member away from the stop plate, and a U-shaped spring fastened to the rectangular locating hole of the stop plate and adapted for engaging in one groove of the heat sink.